Unit 5: States of Consciousness

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sleep: rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur, also known as paradoxical sleep, because muscles are relaxed (except for minor twitches) but other body systems are active O O Every 90 minutes cycle through four distinct sleep stages Discovered by Eugene Aserinsky when he tested an electroencephalograph on his sleeping son ● Procedure repeated Measured brain activity by monitoring brain wave activity, eye movements and muscle tension through electrodes Alpha waves: the relatively slow brain waves of a relaxed, awake state ● In bed with eyes closed, EEG Sleep: periodic, natural loss of consciousness- as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation ● Unremembered ● NREM-1 ● NREM sleep: non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep REM sleep ● ● NREM-2 NREM-3 Marked by slowed breathing and irregular brain waves (stage 1 of REM) - called NREM-1 ● ● Make experience hallucinations O 20 minutes • Sleep spindles - bursts of rapid rhythmic brain wave activity Can be awakened easily, but clearly asleep Hallucinations: false sensory experiences, such as seeing something in the absence of of an external visual stimulus Ex. sensation of falling o Hypnagogic O Can be incorporated into memories (aliens) Slow wave sleep 30 minutes Brain emits delta waves O Delta waves: the large, slow brain waves associated with deep sleep Children wet bed at end of stage About hour after fall asleep, leave NREMf ● Ascend from initial sleep dive Move through NREM-2 to REM sleep REM sleep ● ● • Sleep theories • Breathing becomes rapid and irregular • Every half minute eyes dart around under closed lids ● Announce beginning of dream ● ● 10 min brain waves rapid and saw toothed Heart rate rises ● Whole cycle repeats every 90 minutes ● Genitals become aroused Motor cortex activated, but blocked from messaging by brainstem o Essentially paralyzed (can linger - sleep paralysis) o Not easily awakened Night goes on NREM-3 gets shorter and disappears REM and NREM-2 get longer O 20-25% of average night spent in REM O Remember dreams if woken during REM 23.3 - How do biology and environment interact in our sleep patterns? What affects our sleep patterns? o Biology and environment Genetics Age Culture o Morning light tweaks circadian clock by activating light-sensitive retinal proteins Suprachiasmatic nucleus (SCN): a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN causes the pineal gland to adjust melatonin production, thus modifying our feelings of sleepiness. Exposure to light can disrupt 24 hour clock ● Artificial light delays sleep 23.4 - What are sleep's functions? O Five reasons for sleep Sleep protects • Sleep schedule suits ecological niche ● ● REM vs. NREM ● O O Flip It Video: REM Sleep How do we study sleep? o Sleep is a physiological condition producing a natural loss of consciousness O We can identify sleep and the stages it includes by measuring brain waves with an electroencephalograph (EEG) O O O O Humans safer during day Sleep helps us recuperate NREM ● Restore and repair brain tissue Neurons repair Sleep helps restore and rebuild our fading memories of the day's experiences • Strengthens and stabilizes neural memory ● Remember more after sleeping Sleep feeds creative thinking ● Dreams inspire literary, artistic and scientific achievements Boost to thinking and learning ● Sleep supports growth • Pituitary gland releases growth hormone during sleep REM stand for rapid eye movement, REM sleep is one sleep stage There are three non-rapid eye movement stages of sleep called NREM-1, NREM-2, and NREM-3 REM Low arousal No paralysis No dreams Module 24 : Sleep Deprivation, Sleep Disorders, and Dreams ● 24.1 - How does sleep loss affect us, and what are the major sleep disorders? Sleep deprivation and sleep disorders Can't fight sleep man Effects of sleep loss High arousal Paralysis Dreams Sleep debt cannot be satisfied by one long sleep Most adults will sleep 9 hours when unhindered More sleep = more satisfied in life College and university students are especially sleep deprived Sleep is predictor of depression ● REM helps process emotional experiences Can make you fatter ● Increases ghrelin, hunger arousing hormone and decreases leptin, hunger suppressing partner ● Increases cortisol - stress hormone that stimulates fat production Suppress immune cells that fight off viral infections and cancer • Sleep longer live longer Slow reactions and increases in errors on visual attention tasks Ex. driver fatigue Ex. industrial disasters often happen after midnight (exxon valdez tanker, union carbide, three mile island, chernobyl) • Stanley coren found spring forward and daylight savings have increased accidents after time change ● ● Brain Diminish ed attentional focus and memory consolidation, and increased risk of depression Immune system Suppression of immune cell production and increased risk of viral infections, such as colds ● Fat cells Increased production and greater risk of obesity Joints Increased inflammation and arthritis o Major sleep disorders Heart Increased risk of high blood pressure - Stomach Increased hunger-arousing ghrelin and decreased hunger-suppressing leptin -Muscles Reduced strength, and slower reaction time and motor learning Insomnia: recurring problems in falling or staying asleep ● Persistent problems falling asleep Worsened by stressing about insomnia Common fixes (sleeping pills, alcohol) can aggravate issue ● ● ● Can lead to tolerance - a state in which increasing doses are needed to produce effect Narcolepsy: a sleep disorder characterized by uncontrollable sleep attacks, the sufferer may lapse directly into REM sleep, often at inopportune times Sudden attacks of overwhelming sleepiness ● ● Sleep Apnea: a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings ● Wake up to snort air • Deprives of slow wave sleep ● Sufferers don;t recall episodes next day - don't know they have it Associated with obesity ● Severe cases - person collapses directly into sleep Caused by genes - relative absence of hypothalamic neural center that produces orexin ● Warning signs O ● Loud snoring o o High blood pressure Daytime sleepiness and irritability Relieved by mask device with air pump to keep sleeper's airway open Night terrors: a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during NREM-3 sleep, within two or three hours of falling asleep and are seldom remembered • Mostly children ● Not nightmares Sleepwalking (NREM-3 sleep disorder) and sleep talking (any sleep stage) ● Childhood disorders, run in families • Usually harmless Few recall walking 24.5 What do we dream about? What we dream O Dreams: a sequence of images, emotions, and thoughts passing through a sleeping person's mind, dreams are notable for their hallucinatory imagery, discontinuities and incongruities and for the dreamer's delusional acceptance of the content and later difficulties remembering it ● Can be confused for reality 8 in 10 marked by one negative event/emotion • • Why we dream Commonly failing to do something, being attacked, pursued or rejected, experiencing misfortune Often incorporate previous days' nonsexual experiences and preoccupations Environment can be incorporated into dream Bc of two track mind Anything that happens 5 minutes before sleep is forgotten ● Why We forget dreams 24.3 What are the functions of dreams? O To satisfy our own wishes Sigmund freud-dreams provide a psychic safety valve that discharges otherwise unacceptable feelings Viewed manifest content as a censored symbolic version of its latent content Manifest content: according to freud, the remembered story line of a dream (as distinct from its latent, or hidden content) ● Latent content: according to freud, the underlying meaning of a dream (as distinct from its manifest content) Thought most adult dreams could be traced back to erotic wishes Penis = gun! Dreams help understand inner conflicts No scientific reason to believe this theory ● No penis guns for me ● O To file away memories Dreams may help sift, sort and fix the day's experiences in our memory Link between REM sleep and memory ● Proved by experiments Proved by brain scans O To develop and preserve neural pathways Physiological function - provides brain with periodic stimulation to preserve and expand brain's neural pathways O To make sense of neural static Dreams erupt from neural activation spreading upward from the brainstem Theory Freud's wish-fulfillment O Physiological function Cognitive development To reflect cognitive development ▪ Brain's attempt to make sense from random neural activity Increased activity in the emotion related limbic system (amygdala) during REM sleep See dreams as part of brain's maturation and cognitive development Top-down control of dream content Explanation Dreams provide a "psychic safety valve"-expressing otherwise unacceptable feelings; contain manifest (remembered) content and a deeper layer of latent content-a hidden meaning. Information-proc Dreams help us sort out the day's events and consolidate But why do we sometimes dream essing our memories. about things we have not experienced? Regular brain stimulation from REM sleep may help develop and preserve neural pathways. Neural activation REM sleep triggers neural activity that evokes random visual memories, which our sleeping brain weaves into stories. Dream content reflects dreamers' cognitive development-their knowledge and understanding. I Critical Considerations Lacks any scientific support; dreams may be interpreted in many different ways. This does not explain why we experience meaningful dreams. The individual's brain is weaving the stories, which still tells us something about the dreamer. Does not address the neuroscience of dreams. O Despite different theories, agreed that we need REM sleep REM rebound: the tendency for REM sleep to increase following REM sleep deprivation (created by repeated awakenings during REM sleep) Flip It Video: Why Do We Dream? ● Freud's wish fulfillment ● O ● Each dream has manifest and latent content O The latent content is an expression of inappropriate sexual desire Information processing O When REM sleep is disrupted, people are less likely to remember tomorrow what they learned • Physiological function O REM sleep activity helps stimulate pathways and networks among neurons Neural Activation O Dreams are the brain's attempt to make sense of random activation that occurs during REM sleep • Cognitive development O Dreams reflect changes in cognitive development as a person ages ● Which is right? O We don't know o They are not mutually exclusive O Freud's theory has the least scientific support